check ****ection porgram??

is there any program that check whether pc cable is currently connected to the lan or not??

what i mean is if i had pcs that connected(LAN)..... i want to make sure every pc is connected together..... which mean to check the cable is not loose from the network card..... if loose, shutdown the pc.......

but what i want is a program that make sure all the pcs are connected together.... and if one of those pc cable are loose(network card) the pc will be shutdown or whatsoever to block it from running...... sory if i misunderstanding what u mean....
thanks in advance